The design and construction of auditorium seating is a highly evolved art. In addition to the obvious requirements of comfort and aesthetic effect, the units must have a retracted position providing walking freedom. They must present a minimum of obstruction to the legs and feet of the occupants of both the particular seat and the one behind. Since depth of the structure in the front-rear direction influences row spacing, this factor is also important. Each installation may include thousands of units, so total cost is a prime consideration.
Blending all these design criteria has produced a wide variety of structural details. Most designs include some form of floor-mounted frame, a seat that can be tipped up for walking freedom, and some form of fixed or articulating back. It is rare to find a structure that satisfies all the physical requirements in an economical configuration that has aesthetic appeal.